Abstract: A system for accurately controlling the movement of an object through a predetermined non-rectilinear path in a predetermined volume having X, Y and Z axes. The system uses three tracking laser interferometers rigidly positioned relative to the volume and a single retroreflector rigidly coupled to the object to control movement of the object non-rectilinearly through the volume along a predetermined path. Using two more tracking laser interferometers and an additional retroreflector rigidly coupled to the object, the system controls angular orientation of the object about one of the axes. Adding a sixth tracking laser interferometer and a third retroreflector to the object, the system can also control angular orientation about the other two axes. Each tracking laser interferometer comprises an interferometer and a tracking mirror which is pivoted to maintain the interferometer output beam on its associated retroreflector.

Abstract: In the horizontal drive of a raster scanned video display, a free running astable multivibrator responsive to a synchronization input signal provides a horizontal output signal to horizontal deflection circuitry for synchronizing the video display's raster scan with the video information presented thereon. The astable multivibrator includes a pair of coupled transistors which are alternately rendered conductive in accordance with the time constant of a respective RC network associated with each transistor. To compensate for the temperature-dependent operation of the transistor pair which causes the multivibrator's operating frequency to increase with increasing temperature, a pair of back-to-back coupled diodes are connected to provide the synchronization input signal to one RC network so as to increase the charge on a capacitor within the network, the time constant of which is similarly increased. The temperature-dependent change in voltage across the diodes compensates for the change in V.sub.

Abstract: A method and an apparatus for optical inspection of transparent articles. The method and apparatus use a light beam scanning field which is separated into at least two portions. The field portions are directed at the article at differing angles of incidence such that they eliminate blind spots caused by portions of the apparatus which block the passage of the light through the article. A feature of the invention is its provision of a folded optical path to increase the length the beam travels between the beam generator and the object beyond the physical distance between the beam generator and the object.

Abstract: In a demodulation circuit, a timing synchronizing circuit generates a timing signal representing a sampling timing of an A/D converter and has a timing signal generator, a polarity identification circuit and a logic circuit. The timing signal generator is phase-controlled by a phase control signal and generates a timing signal. The polarity identification circuit identifies a polarity of a differential coefficient of the baseband signal at a sampling point of the A/D converter and generates a polarity identification signal. Upon logic processing, the logic circuit supplies to the timing signal generator the phase control signal representing a deviation of an actual sampling point of the baseband signal from an optimal sampling point. A carrier asynchronism detection circuit detects an asynchronism state of a carrier regenerating circuit and supplies to the timing synchronizing circuit a signal which changes its loop parameter.

Abstract: An auto-focus system for focusing reflecting objects which are under investigation in a measuring device. The invention comprises a light source for producing an illumination beam for illuminating an object plane of an objective lens to be focused, an imaging beam and a focusing beam, both originating from the illuminated object, means for separating the focusing beam and the imaging beam, the latter producing an image of the object in an image plane which is evaluated, and an amplitude object not visible in the imaging beam. Means are provided to render visible the amplitude object in two detector planes, where resulting counter moving interference patterns are evaluated and used for focusing the objective lens.

Abstract: A improved microwave dielectric oscillator module which is provided with a removable temperature compensated dielectric resonator channel element is described. The removable temperature compensated dielectric resonator channel element cooperates with an electrically shielded housing. A substrate is mounted within the housing. Microstrip or stripline conductive patterns deposited on the substrate couple energy from the removable dielectric resonator to the remainder of the oscillator circuitry. The oscillator achieves wideband operation utilizing a GaAs FET transistor as the oscillators active element in conjunction with an intergral trombone-line phase adjuster.

Abstract: An infrared detection module is disclosed for interfacing a plurality of detector elements to external electronics. The module is formed of a plurality of multi-channel integrated circuits stacked in substantially overlapping registry with adjacent integrated circuits separated by an insulating layer. Each integrated circuit is formed to have exposed conductive areas along first and second edge portions thereof. Each detector array segment is disposed transverse to the plane of the integrated circuits and connected to conductive areas on each integrated circuit along first edge portions thereof. A module header interface is disposed transverse to the plane of the integrated circuits and is electrically connected to the conductive areas along the integrated circuit second edge portions.

Abstract: Disclosed is a stroboscopic method of determining the quality of meshing between respective teeth of two or more gears. By way of example, a method is disclosed by which a standard is established by directing an adjustable pulse rate light beam (L) from a stroboscopic light source (18) towards a region (R) generally encompassing the location of meshed engagement between respective teeth (6; 8) of a pair of gears (2, 4) rotating at a predetermined rpm that are selected on the basis that they possess degree of mesh engagement quality desired for such gear pairs.

Abstract: A directly modulated microwave source for use in communications equipment is disclosed. The arrangement, fabricated in an open ended waveguide comprises an oscillator section operating in the TE.sub.101 mode and an impedance matching section providing adjustable coupling to a load. A suitable active element is a Gunn diode, post mounted in proximity to the closed end of the waveguide for H field coupling. Modulation in frequency or phase is achieved by a varactor diode, also post mounted, positioned approximately 2/3 of the length of the waveguide from the closed end. A vertically adjusted post for the load coupling adjustment, is placed adjacent the varactor post, but nearer the opening. The two adjacent posts define the boundary between sections and provide H field coupling to the varactor diode. Temperature stabilization means and frequency tuning means are located respectively on the upper and lower surfaces of the waveguide at anti-nodial portions of the oscillator section.

Abstract: A circuit for generating a noise signal for use in a jet engine noise simtor which utilizes two component pseudo-random noise (PSN) generators and a combination field effect transistor (FET) and resistor circuit to which the outputs of the PSN generators are connected such that the signal from one PSN generator is modulated by the signal from the other PSN generator.

Abstract: A phase locking circuit for effecting pull-in of a phase locked loop to a desired frequency component even in the presence of spurious signals includes a phase locked loop, a scanning circuit and a control circuit. The scanning circuit generates a scanning current to the phase locked loop which activates a voltage controlled oscillator (VCO) therein, the VCO output being phase locked to an input signal by operation of the phase locked loop. The control circuit produces a periodic scanning restart signal causing the scanning circuit to periodically generate a second scanning current independent of the phase lock status of the phase locked loop until a phase lock to the desired frequency component is realized. The second scanning current functions to unlock a VCO output locked to a spurious signal.

Abstract: An improved method and apparatus for reducing the amount of memory required to implement a digital echo modulator. A single permanent memory stores digital representations of a series of samples of a signal element for several phases of the signal element. A temporary memory is provided to store the digital representations from a plurality of signal elements to be overlapped. The signal element values are clocked out of the permanent memory and into the temporary memory at a rate, during each sampling interval, equal to the number of overlapping signal elements. The contents of the temporary memory are then provided to a summation circuit for producing a digital representation of the composite signal during that sampling interval. Phases of the signal element which are 180.degree. out of phase with the stored phases are generated using two's complement circuitry.

Abstract: A demodulator circuit comprises an integrator (A1) having its input connected through a first switch (S1) to a summing point (P). A modulated carrier signal to be demodulated is applied to the summing point through an input resistor (R1). A sample-and-hold circuit comprises a second switch (S2) operable at the carrier signal frequency in antiphase with the first switch (S1) to connect the output of the integrator (A1) to a holding capacitor (C2) and an operational amplifier (A2) having 100% negative feedback. A feedback connection including a feedback resistor (R2) is connected between the output of the amplifier (A2) and the summing point (P).

Abstract: An oscillator circuit including an odd number of inverters connected in cascade to form a loop; a delay element inserted between adjacent inverters; and a pulling circuit. The pulling circuit pulls up and/or pulls down the potential of the output terminal of the delay element during a predetermined period in response to the inversion operation of one of the inverters.

Abstract: A circuit for reducing the distortion in an FM quadrature demodulator. A non-linear circuit stage is connected after the quadrature demodulator, whose characteristic has an inverse curve form like the demodulator characteristic. If the FM quadrature demodulator uses a resonant circuit to generate a frequency-dependent phase shift and has two outputs in phase opposition, the non-linear circuit stage can be formed by two diode branches through which the output currents of the quadrature demodulator flow. The voltage difference at these two diode branches supplies the output signal with the non-linear distortions largely removed.

Abstract: A solid state oscillator circuit for operation at very high frequencies includes a field effect transistor having an input network connected between its gate and source electrodes and an output network connected between its drain and source electrodes, the input and output networks each including three discrete capacitors connected in a "pi" configuration, the input and output networks being connected in series with one another, and an inductor being connected in parallel with the series connected networks, the equivalent circuit impedance of the networks in series and the inductance determining the operating frequency of the oscillator circuit, and the relative ratio of impedance of the networks determining the amount of oscillator feedback.

Abstract: A projection exposure apparatus for projecting, onto a semiconductor wafer through a projection lens, an integrated circuit pattern formed on a mask or reticle. An alignment beam having a wavelength different from that for the exposure is used to achieve alignment between the mask and the wafer. A parallel flat plate is detachably disposed between the projection lens and the mask and/or the wafer to prevent a magnification error and/or a focus error of the projection lens which would otherwise be caused upon alignment due to the difference in wavelength.

Abstract: There is provided an indirect frequency synthesizer in the millimeter wave frequency range of 36 to 38.6 GHz. The synthesizer comprises a high performance frequency translation loop for operation in the microwave frequency range and contains a voltage-controlled oscillator, an automatic loop gain correction system and a sophisticated lock search system. The frequency translation loop is operable under a variety of conditions (temperature etc.) and overcomes the considerable difficulties which exist in this frequency range such as maintenance of constant optimum loop parameters, thus making it possible to utilize the entire frequency tuning range of the millimeter wave oscillator. As a result, the synthesizer has very satisfactory characteristics as regards noise and spurious frequencies products.

Abstract: In a demodulator circuit for processing a frequency-modulated (fm) signal, two rectangular-wave signals of opposite phase are generated from the fm signal and separately processed in two similar circuit paths. Each circuit path includes an inverter that receives one of the rectangular-wave signals and a NOR gate that receives both the rectangular-wave signal and its inverted version from the inverter. By imparting a slight delay on positive-going transitions of the inverted signal, a pulse stream is produced by the NOR gate in coincidence with such transitions. The pulse streams from both paths are combined to obtain a resultant signal having a pulse repetition rate that is twice the frequency of the fm carrier. Temperature-caused pulse variations in one circuit path relative to the other . . . which will allow the fundamental carrier frequecy to reappear . . . are stabilized by having the inverters, and the NOR gates, in thermally-coupled packages.

Abstract: A tracking phase locked loop circuit in which the frequency of an oscillator portion thereof is varied over a range of frequencies in search of an incoming carrier is disclosed. The varying frequency occurs at two different sweep rates. A faster rate is used until the frequency of the phase locked loop's oscillator nears the frequency of the incoming carrier, and a slower rate is used until the circuit locks onto the carrier. A filter couples between mixer and sweep control circuit portions of the phase locked loop to provide information concerning the difference between oscillator frequency and incoming carrier frequency. The sweep control circuit distinguishes between the carrier and noise and switches rates accordingly.